A particular problem has existed in the compacting of bundles of firewood. Since firewood is made by splitting logs endwise each log has a much different shape and can have a different volume at one end than at another.
For this reason a compacted bundle of logs will be smaller at one end than at another in most cases. However, the firewood compactors of the past have had fixed and moveable jaws adapted to extend the length of a bundle of firewood, but in which the compartment resultant from the closing of the fixed and moveable jaws with respect to each other against the firewood has the same cross-sectional area on forward and rearward parts thereof whereby one end of a bundle of firewood has been compacted to a lesser extent than the other to the end that a certain amount of looseness is undesirably present.
Firewood compactors of the past have had a place for application of a strap disposed between forward and rearward pairs of jaws, each pair of having a fixed jaw and a moveable jaw. However, when a strap is applied to a bundle as tightly as possible, there is yet an undesirable looseness in many cases because the ends of a bundle of firewood were not completely compacted because of the rigid connection of forward and rearward moveable jaw elements, which latter gave no possibility to adjusting to bundles of firewood having a lesser cross-sectional size at one end of the bundle than the other.
It is an object of this invention to solve this problem by eliminating the use of a single pressure cylinder for operating both forward and rearward moveable jaw elements as has been the characteristic of prior art machines, and further to replace this with the concept of independent actuators, independent pressure cylinders arranged for controlling the moveable jaws so that a rearward moveable jaw element can compact tightly down against a bundle of firewood as far as the firewood will allow the compaction to proceed within the pressure limits of the machine, the forward moveable jaw element being able to likewise compact the firewood to the pressure limit of the machine so that uneven firewood bundles are completely compacted to the desired extent at both the forward and rearward ends of a bundle.
It is a particular object to make possible the tight application of a strap to the center of an uneven bundle of firewood because of this concept of independent actuation of forward and rearward moveable jaw elements.
Firewood compactors of the prior have had moveable jaws which move vertically toward fixed jaws without the moveable jaws having any connection to the frame except through the pressure cylinder assembly.
It is an object of this invention to connect the moveable jaw elements hingedly to the frame at one side of the firewood receiving cavity thereof, and to so position the pressure cylinders that they cause a hinging by exerting a pressure to force the other side of the moveable jaws downwardly for compounding the available pressure at the cylinder assemblies with the great leverage achieved by having one side of the moveable jaws hingedly attached to the frame. In this way an eight inch cylinder expansion can cause a four inch compression at the center of my moveable jaw cavity for compounding the pressure to insure that the bundle of firewood is strapped so very tightly as to be much more likely to stay together during the rough handling and throwing involved in firewood shipment.
Compacting and strapping machines of the prior art have been useful for only making a bundle of a specific size.
Another object of this invention is to provide insert plates having a cavity therein for forming the effective ultimate jaw cavity of the moveable jaws and with the insert plates being removeable and replaceable so that a plate of lesser or greater size can be used for varying the size of the firewood receiving chamber so that the same machine can be used for compacting larger or smaller firewood bundles as desired.
A further object of the invention is to eliminate the problems involved in electrical contact points in electrical circuitry of the prior art in which the dirt commonly found on firewood tends to contaminate the area and the electrical contact points, all this being replaced with pressurized air circuitry by this invention, the air intake port being provided with dust filter for dependable operation.
An objective of this invention is to provide automatic cycling. This means that a single pressing of a valve button will cause the automatic occurrence of everything necessary to bring about a jaw closing and a strapping, a jaw opening and a bundle ejection, all in their proper sequence.
Still another objective is to provide a firewood compactor-strapper which has air actuated timing which is automatic and adjustable.
Because logs have knots causing the grain to curve, the splitting of a log from one end will cause the surface of the split side to have a large bump on it. This causes a log to have a greater effective volume in a bundle at the end where the knot protrudes. In using compactors of the prior art it has been necessary to slowly and carefully select logs to be placed in a given bundle so that the ends of the bundle come out even enough to prevent the strapped bundle from being excessively loose, and an objective hereof is to provide independent forward and rearward jaw cylinder actuation so that logs need not be selected but can be thrown into the machine at random and will still emerge tightly bound.
The further object of the invention is to provide pneumatic circuitry for controlling automatic cycling including jaw closing and opening in which the cylinders for closing the jaws are not pneumatic which would provide less power, but hydraulic because of the non-compressability of liquids giving unlimited amounts of power directly proportional to the horse-power input on the hydraulic pump. This is far superior to compressing air at the very high pressures needed to do the same job because the compressing of air is extremely difficult to the point of being impossible with ordinarily available and affordable air compressor facilities.
A further object of the invention is to provide the use of hydraulic cylinders even though the circuitry is pneumatic because of the safety factor. Since highly compressed air is in danger of rupture of lines, a rupture of a hydraulic line, even under great pressure, is all over immediately without much consequence because all pressure is relieved with a minute amount of motion. However, when pneumatic equipment has a ruptured line, then the air shooting out of the rupture moves great distances at high speeds propelled by all of the air compressed back through the entire system, leaving the possibility of the blowing off of fingers of an operator or his eyes being blinded by the compressed air jet.
However, I conceive of a pneumatic system for use with the hydraulic system that would be at very low pressure such as ninety pounds per square inch pressure. For instance, air at fifty pounds or one-hundred-fifty pounds does exactly the same thing. For instance, five pounds would work; one-hundred five pounds with special equipment would work; at over one-hundred thirty pounds, the pumps aren't even made for air compressing, unless they're super expensive, although they will go to four thousand pounds if super expensive.
A particular objective is elimination of electrical circuitry for control of the automatic cycling. Electrical circuitry has the disadvantage that switches become contaminated with dust, moisture, and in some cases even explosive gasses, so that under the rugged conditions in which a machine might be used, it is far superior to have my concept of a pneumatic circuit for automatic control of a compactor strapper.
Another objective of this invention is to provide in the pneumatic control circuit a pneumatic rotary timer or, better yet, an air plunger timer having adjustable plunger speeds for controlling the sequence of the various operations of the compactor and for regulating the timing of each to an ideal. In a rotary timer it is rotating cams that open and close valves, and the only way the timing can be varied, is by changing the rotating speed of a cam nose. There are two ways of initiating the rotary action, one way is electrical and the other way is pneumatic. The electrical revolves a miniature motor and reduction gear, in which latter it is very difficult to change speed. The pneumatic timer ways available on the market are mostly a pair of duo-cylinders which give an overlapping reciprocation which is a mechanism that is also difficult to change the speed of, or in other words, the timing of the occurrence of each sequence of the operation.